Accurate measurement of the electron beam polarization in JLab Hall A using Compton polarimetry

S. Escoffier (1) , P.Y. Bertin (2) , M. Brossard (2) , E. Burtin (1) , C. Cavata (1) , N. Colombel (1) , C.W. de Jager , A. Delbart (1) , D. Lhuillier (1) , F. Marie (1) , J. Mitchell , D. Neyret (1) , T. Pussieux (1)

1 DAPNIA - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
2 LPC - Laboratoire de Physique Corpusculaire - Clermont-Ferrand

A major advance in accurate electron beam polarization measurement has been achieved at Jlab Hall A with a Compton polarimeter based on a Fabry–Perot cavity photon beam amplifier. At an electron energy of 4.6 GeV and a beam current of 40 $\mu$A, a total relative uncertainty of 1.5\% is typically achieved within 40 min of data taking. Under the same conditions monitoring of the polarization is accurate at a level of 1\%. These unprecedented results make Compton polarimetry an essential tool for modern parity-violation experiments, which require very accurate electron beam polarization measurements.

Mots clés: Compton polarimeter; optical cavity; polarized beams

Domaines: Instrumentations et Détecteurs [physics.ins-det]

S. Escoffier, P.Y. Bertin, M. Brossard, E. Burtin, C. Cavata, et al.. Accurate measurement of the electron beam polarization in JLab Hall A using Compton polarimetry. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2005, 551, pp.563-574. ⟨10.1016/j.nima.2005.05.067⟩. ⟨in2p3-00024386⟩